In a bowl, combine the chicken breasts with the teriyaki sauce and sesame oil. Let it marinate for at least 30 minutes or as short as 10 minutes if you're in a hurry.

In a medium saucepan, combine the sushi rice and water. Bring it to a boil, then reduce the heat to low, cover, and let it simmer for about 15 minutes or until the water is completely absorbed.

Once done, remove it from the heat, and let it sit covered for another 10 minutes.

In a small bowl, mix the rice vinegar, sugar, and salt until dissolved. Once the rice is done resting, fluff it with a fork and gently mix in the vinegar mixture.

While the rice is resting, grill or pan-cook your marinated chicken on medium heat for about 6-7 minutes on each side until fully cooked. Let it rest for a few minutes before slicing.

Take a round mold or small bowl and begin layering. Start with a base of sushi rice, followed by sliced teriyaki chicken, then your avocado. Repeat this process until you reach the top, pressing gently so everything holds together.

Carefully remove the mold and transfer your stack onto a plate. Sprinkle sesame seeds and chopped green onions on top for that gourmet touch.